running a class with main from a servlet in j2EE

How to (or can i) run a class with main() from a servlet??

i want to take input from a html page and insert data into a database using hibernate.

-i have an annotated class.

-a class having main(), running which inserts the data into the database.

-and a servlet with post method code:

String input_from_html=request.getParameter("input_from_html");

I need to put the data 'input_from_html' to the class with main() and run the class,which should happen once the submit button in the html page is pressed.